Fever of unknown origin in a patient with ulcerative colitis: Do not forget large vessel vasculitis.

We report the case of a patient with ulcerative colitis (UC) who, 4 years after diagnosis, developed large vessel vasculitis (LVV), revealed by high fever, joint pain and headache. Laboratory tests showed C-reactive protein at 326mg/L, leukocytosis at 18.9 G/L, with 14.2G/L of neutrophils and elevated serum IL6 (12pg/mL [N 0.76-6.38]). Thoraco-abdominal CT scan was normal, apart from evidence of involvement of the rectum and colon consistent with UC. The diagnosis of LVV was established by a positron emission tomography (PET-CT) scan that revealed thoracic and abdominal aortitis.